This invention relates to woodwind instrument and, more particularly, those types of woodwind instrument equipped with key mechanisms for closing holes formed in tubes.
The woodwind instrument has a wide variety of family members such as, for example, flutes, recorders, clarinets, oboes, saxophones and bassoons. Although the word xe2x80x9cwoodwindxe2x80x9d is a compound word produced from the words xe2x80x9cwoodxe2x80x9d and xe2x80x9cwindxe2x80x9d, the word xe2x80x9cwoodwindxe2x80x9d does not imply the material of the wind instruments. The bassoons and clarinets are usually made of wood. However, the saxophones are made of metal. Several family members such as flutes are directly blown by players. On the other hand, players require reeds for other family members. The players blow the clarinets by means of reeds, by way of example. Although the players give rise to vibrations of air columns in different manners, they are the family members of the woodwind instrument. Nevertheless, all the family members of woodwind instrument have tubes formed with holes, and the players selectively open and close the holes for changing the pitch of notes emitted. The tubes of recorders are not so long that the players can selectively open and close the holes with their fingers. However, the flutes, saxophones, oboes and bassoons have the tubes formed with the holes, which are widely spaced from one another. The intervals are too long for the players to selectively open and close them with their fingers. For this reason, these family members require unique key mechanisms. The present invention appertains to those family members of the type having the key mechanisms.
A flute is, by way of example, broken down into a tube, which may be separable into plural parts, and a key mechanism. The tube is formed with a mouthpiece and holes. The mouthpiece is formed at one end portion of the tube, and the holes are arranged along the centerline of the tube toward the other end. The key mechanism includes plural keys, with which a player selectively opens and closes the holes for changing the pitch of tones.
FIG. 2 illustrates the prior art key 4 incorporated in the flute. The prior art key 4 is broken down into a pad 10, a pad cup 11 and a fastener 12. The pad cup 11 is formed of metal or alloy, and has a recess where the pad 10 is snugly received. The fastener 12 prohibits the pad 10 from being unintentionally separated from the pad cup 11. A tone hole chimney 5 encircles one of the holes 2 formed in the tube, and the upper edge 5a of the tone hole chimney 5 is rounded. The pad 10 is pressed to the rounded edge 5a for closing the hole 2.
The pad 10 is to be air-tight, adaptable and durable. While a player is playing on the flute, the moist breath passes through the tube, and vents through the hole 2, which the player keeps opened. The pads 10 are expected to confine the wet air in the tube. If the breath is leaked through the pads 10, the tones become unstable, and the player feels the pitches, loudness and timbre less controllable. In order hermetically to seal the breath in the tube, the pads 10 are expected to adapt themselves to the holes 2. Thus, the pads 10 are to be adaptable and airtight.
The pads 10 are exposed to the wet air during the practice and performance. Although the player wipes the condensate from the inner wall of the tube 1 after the practice, the condensate is liable to be left on the pads 10. The pads 10 are dried until the next practice/performance. Thus, the pads 10 are repeatedly exposed to the wet air and dried thereafter. Nevertheless, the pads 10 are expected to maintain the adaptability and the air-tightness. If the pads 10 lose the adaptability and air-tightness within a short time, the player frequently changes the pads 10 from the waste ones to new pieces. The exchange work is time-consuming, and players hate it. For this reason, the pads 10 are to be durable.
From those viewpoints, the pad 10 is designed to have a core 10a/15 and a sealing layer 10b. The core 10a/15 imparts the adaptability to the pad 10, and the sealing layer 10b makes the pad 10 airtight. A core layer 10a and a backing cardboard 15 as a whole constitute the core. The backing cardboard 15 is made of paper, and the core layer 10a is made of air-permeable material such as compression felt. The core layer 10a is laminated on the backing cardboard 15, and sealing layer 10b is fixed to the core layer 10a reverse to the backing cardboard 15. The sealing layer 10b is expected to hermetically seal the air column inside the tube. Skin and bladder are available for the sealing layer 10b. It is preferable to make the sealing layer 10b from sheepskin, calfskin and bladder of sheep and calf. The pad 10 is formed with a center hole. The center hole is increased in diameter from the core/sealing layers 10a/10b to the backing cardboards 15 so that a step takes place at the boundary between the backing cardboard 15 and the core layer 10a. 
The pad cups 11 are formed from a sheet of metal/alloy through a drawing. Each of the pad cups 11 has a peripheral wall portion 11a so as to define the recess. The recess has an inner diameter substantially equal to the outer diameter of the pad 10 so that the pad 10 is snugly received in the recess. However, the recess has the depth greater than the thickness of the pad 10. A player directly depresses the pad cups 11 with his or her fingers, and pushes levers, which are connected through shafts to the other pad cups 11, with his or her thumb and fingers for closing the holes 2. When the player removes the force from the pad cups 11 or the levers, return springs make the pad cups 11 open.
The fastener 12 consists of a center nut 13, a bolt 14 and a circular plate 12a. The center nut 13 is brazed to the inner surface of the pad cup 11, and an internal thread is formed along the centerline of the center nut 13. The center nut 13 has an end surface 13a where the internal thread is open, and the end surface 13a is flat. The center nut 13 has a wide boss portion substantially equal in diameter to the hole formed in the backing cardboard 15, and the remaining portion is substantially equal in diameter to the hole passing through the core layer 10a and the sealing layer 10b. Thus, the center nut 13 is snugly received in the center hole of the pad 10.
The bolt 14 has a head portion 14a and a threaded stem portion 14b, and the threaded stem portion 14b projects from the reverse surface of the head portion 14a. The reverse surface of the head portion 14a is also flat.
The circular plate 12a has major surfaces, which are also flat, and is formed with a hole at the center area thereof. The hole in the circular plate 12a has an inner diameter greater than the outer diameter of the threaded stem portion 14b so that the threaded stem portion 14b loosely passes through the hole formed in the circular plate 12a. The circular plate 12a has an outer diameter less than the outer diameter of the pad 10 and, accordingly, the inner diameter of the recess.
The key 4 is assembled as follows. An assembling worker puts the pad 10 into the recess. The center nut 13 is inserted into the center hole of the pad 10, and the flat end surface 13a is inside the center hole. Subsequently, the assembling worker puts the circular plate 12a on the sealing layer 10b, and aligns the hole formed in the circular plate 12a with the hole formed in the center nut 13. The assembling worker inserts the threaded stem portion 14b into the center nut 13, and turns the bolt 14. The threaded step portion 14b is brought into threaded engagement with the center nut 13, and the bolt 14 is screwed into the center nut 13. The flat reverse surface of the head portion is brought into face-to-face contact with the flat major surface of the circular plate 12a, and the head portion 14a is pressed against the circular plate 12. The circular plate 12a in turn presses the pad 10 to the boss portion of the center nut 13. Thus, the pad 10 is fastened to the pad cup 11 by means of the fastener 12.
Assuming now that the pad cup 11 was mistakenly brazed to the arm, the center line of the column 13 is inclined with respect to the centerline of the tone hole chimney 5 by xcex8 as shown in FIG. 2. If the pad 10 is fastened to the pad cup 11 without any regulation, the pad 10 is also inclined with respect to the centerline of the tone hole chimney 5. When a player depresses the key 4 to the tone hole chimney 5, the pad 10 is imperfectly brought into contact with the upper edge 5a, and clearance takes place between the pad 10 and the tone hole chimney 5. This results in leakage of the breath. For this reason, if the angle xcex8 is not serious, the assembling worker tries to regulate the pad 10 to the appropriate position.
The assembling worker inserts an adjusting shim 18 between the backing cardboard 15 and the pad cup 11. The adjusting shim 18 is made of paper, and makes the pad 10 spaced from a certain area on the inner surface of the pad cup 11. If the pad 10 is appropriately regulated by means of the adjusting shim 18, the centerline of the tone hole chimney 5 is normal to the pad 10, and the pad 10 is brought into contact with the entire upper edge of the tone hole chimney 5. The pad 10 prevents the hole 2 from leakage of the breath. However, a problem is encountered in the prior art keys 4 in that the breath is still leaked through some holes 2 after the regulating work.
It is therefore an important object of the present invention to provide a woodwind instrument, a key mechanism of which perfectly close and open holes formed in a tube after a regulating work.
The present inventors investigated the problem inherent in the prior art key, and found that the circular plate 12a was strongly pressed against the certain portion of the pad 10 where the adjusting shim 18 had been inserted. A dent was formed in the certain portion, and gap 17 took place between the upper edge 5a and the pad 10 in the vicinity of the dent. The breath was leaked through the gap 17.
The present inventors reasoned from the structure of the prior art key 4 as follows. The center nut 13 was inclined with respect to the centerline of the tone hole chimney 5, and the pad 10 and circular plate 12a were perpendicular to the centerline of the tone hole chimney 5 under the condition that any force was not exerted on the circular plate 12a. Since the bolt 14 was screwed into the inclined center nut 13, the head portion 14a proceeds toward the circular plate 12a along the inclined centerline of the center nut 13. The flat reverse surface of the head portion 14a was partially brought into contact with the certain area in the flat surface of the circular plate 12a. The head portion 14a exerted the force on the certain area, and caused the circular plate 12a to be inclined with respect to the centerline of the tone hole chimney 5. This resulted in the face-to-face contact between the flat reverse surface of the head portion 14a and the flat surface of the circular plate 12a. Since the head portion 14a uniformly exerted the force on the flat surface of the circular plate 12a, the circular plate 12a was forced to move along the inclined centerline of the center nut 13. Although the pad 10 resisted against the circular plate 12a, the sealing/core layers 10b/10a was deformable so that the circular plate 12a made the dent in the pad 10. The present inventors concluded that the dent and, accordingly, the clearance were resulted from the circular plate 12a, which changed the attitude when the head portion 14a was brought into contact therewith.
To accomplish the object, the present invention proposes automatically to regulate a pad washer to be in parallel to a pad while a bot is being screwed into a center nut.
In accordance with one aspect of the present invention, there is provided a woodwind instrument for generating tones through a vibrating column of air comprising a tube having an inner space where the vibrating column of air takes place and plural holes connecting the inner space to the atmosphere and a key mechanism including a linkage fixed to the tube and plural keys supported by the linkage over the plural holes and changed between respective open positions at which the holes are opened and respective closing positions at which the holes are closed, and each of the keys has a pad cup connected to the linkage and formed with a recess, a deformable pad received in the recess and held in contact with a periphery of the tube defining associated one of the holes at the closing position, a adjusting shim inserted between the pad cup and the deformable pad, if necessary, in order to cause the deformable pad to be held in contact with the entire periphery of the tube defining the associated one of the holes at the closing position, a fastener connected to the pad cup and exerting force on the pad for pressing the deformable pad and the adjusting shim, if any, to the pad cup and an automatic regulator provided in association with the fastener and causing the force to be substantially uniform over a contact surface between the fastener and the deformable pad.